President John F. Kennedy signs the Limited Test Ban Treaty in October 1963, banning nuclear arms tests in the air, in space and under water, but not under ground. It was a precursor to the 1968 Nuclear Non-Proliferation Treaty. Watching from left are Senator John Pastore, Under Secretary of State Averell Harriman, and senators Fulbright, Smathers and Aiken. Signed by the United States, the Soviet Union and the United Kingdom, the treaty allayed fear of the danger of atmospheric nuclear fallout. Two of the then five world nuclear powers — France and China — were not included in the treaty.